Nine months after the Senate Intelligence Committee published a scathing report on the U.S. torture of detainees after the Sept. 11 attacks, Amnesty International USA is demanding an investigation into the lackluster and "inconsistent" response by Justice Department officials.

The alleged inaction by federal authorities has allowed interrogators to evade responsibility for the abuse and cloaked the government's failure to punish any wrongdoers, Amnesty said.

NPR has obtained a formal complaint the group filed with Justice Department Inspector General Michael Horowitz Monday afternoon. The document said leaders at the Justice Department have provided conflicting accounts about who if anyone there has read the complete version of the nearly six-year-long Senate study, commonly known as the "torture report."

The Senate study reported stark new details about mistreatment, including that 119 detainees were held in CIA custody and at least five of them were subjected to forced "rectal feeding" and "rectal hydration."

More importantly, Amnesty lawyers said, federal authorities have "not established a process for assessing any new evidence of criminal wrongdoing that the full report provides."

The 25-page Amnesty complaint described clashing statements by top DOJ officials about their familiarity with the report. In her Senate confirmation hearing this year, Attorney General Loretta Lynch told lawmakers she would read the executive summary of the Intelligence Committee report. And in separate testimony, in March, FBI Director James Comey told Sen. Dianne Feinstein, D-Calif., that he had read a summary and "a small number of people at the FBI ... have read ... the entire thing."

But in court filings in a Freedom of Information Act case, Justice Department lawyers said neither DOJ (which oversees the FBI) or the State Department had opened packages with a computer disc that contained the full report, more than 6,000 pages long. And in comments to reporters after the executive summary became public, a Justice Department spokesperson said investigators had reviewed the report but that they "did not find any new information that they had not previously considered."

Amnesty lawyers said they didn't know why the Justice Department had issued several apparently conflicting accounts of its handling of the Senate report, but in their complaint they cited the possibility that authorities were "engaging in a cynical and hyper-technical effort to circumvent open records law ... and prevent the release of the full report to the public."

"The U.S. government as a matter of international human rights law is required to investigate evidence of human rights violations and the Justice Department itself is charged with investigating violations of federal law," Naureen Shah, director of Amnesty's security with human rights program, told NPR in an interview. "If torture doesn't warrant a Justice Department investigation, I don't know what does."

The Justice Department did appoint a career prosecutor, John Durham, to look into the destruction of videotapes that depicted abuse of detainees. Later, authorities expanded Durham's mandate to consider whether any laws had been broken in the brutal interrogations. DOJ leaders closed the investigation in 2012 without filing any criminal charges. Then-Attorney General Eric Holder Jr. said the prosecutors' effort had been hampered by legal memos written by Justice lawyers during the George W. Bush administration. Those memos approved sleep deprivation, simulated drowning, slapping and other harsh interrogation methods and could be cited in any defense were a case to be brought.

The public fight over those methods continues. Recently, former CIA officials published a book called Rebuttal, which took issue with the findings of the Senate Intelligence Committee. Shah, of Amnesty International USA, said that makes the alleged foot-dragging by the Justice Department even more worrisome.

"We've got former U.S. government officials who authorized or condoned torture at the time who are now out there writing memoirs celebrating their own role in torture and the Justice Department is refusing to do anything about it," Shah told NPR.

Representatives for the inspector general and the Justice Department declined comment.